The present disclosure relates to phase memory, and more particularly to an accumulator-based phase memory.
Phase memory is used to support generation of multiple time-interleaved coherent output frequencies in a radar, electronic warfare, or other communications system that uses only a single RF channel. Phase memory allows a local oscillator (LO) and its associated radio frequency (RF) up/down converters to switch from one LO frequency to another LO frequency (or to multiple LO frequencies) and then back to the first LO frequency while maintaining phase, allowing the single RF channel to be time-multiplexed with many frequency bands. If the phase of the signal is not coherent upon a switch (i.e., as if LO had never left a previous frequency), the signal may be cancelled out or processed incorrectly at a receiver.
Phase memory may be used for switching frequencies in, for example, a RF system or subsystem that is used in a jammer for an electronic warfare applications. To exploit radar's coherent processing interval (CPI) gain in an electronic warfare application, a jammer outputs a phase-coherent pulse train. Generated jammer transmissions must appear to be cut from a phase-continuous sine wave in order to be effective at the receiver (e.g., the victim radar).